For high-speed transmission of signals, parallel data may be serialized for transmission as high-speed serial data and then deserialized upon receipt to return such data to parallel form. An interface for such operation is commonly referred to as a SerDes (Serializer/Deserializer), including a parallel to serial convertor and serial to parallel converter.
However, as the SerDes speed increases, the high-speed data rate will generate ISI (Inter-Signal Interference), thus limiting speed of operation of the interface. In most cases, the line driver is the main bottleneck blocking increased speed of transmission, with the issues arising at least in part because of heavy loading at the line driver output.
The loading on the line driver may include capacitance of the driver itself, ESD (Electro-Static Discharge) capacitance, package capacitance, PCB (printed circuit board) trace capacitance, and common choke parasitic capacitance. The result of such loading is that the line driver becomes bandwidth limited, and thereby limits the operation of the serial interface.